7.7.4 Creating Multiple Relationships

When a relationship is created between two entities, inherited element(s) will be added to one of the entities. For example, if the Order entity has a refers to relationship with the Customer Entity, then the identify attribute of Customer Number becomes an inherited element in the Order entity. In this example, the Order entity has only one element named Customer Number and you may successfully build this model.

When more than one relationship is created between to entities, then the inherited element will appear more than once. For example, the Customer entity might include the Address conceptual entity twice as follows:

Customer includes a billing Address.

Customer includes a shipping Address.

A descriptive prefix such as "billing" and "shipping" can be used to name the inherited elements from the two different relationships, but the underlying field names will be the same. To successfully build this model, you must have unique field names for all elements in the entity. Hence, you must change the field names of inherited elements in the file to ensure that they are unique. For example, you might add a suffix such as SHP to the field names of the inherited elements used for the shipping address. An element with a field name of POSTCD could be renamed POSTCDSHP.